1. Field of the Invention
The invention pertains to a lock system which comprises an access authorization device, which consists of a stationary part in the vehicle and a mobile part carried by the authorized person. A specific function in the lock or in the vehicle is triggered upon the initiation and successful completion of a data exchange between the mobile part and the stationary part.
2. Description of the Related Art
It is known that a capacitative sensor in the handle can be used to initiate this data exchange (DE 196 17 038 C2). This sensor creates a uniform field in the area of the handle and responds when a human hand approaches the field. Then the previously mentioned data exchange begins; and, upon completion of this exchange, the function by which the lock is switched to its release position is triggered. This lock system offers the advantage that the lock is switched to its release position even before the handle is actuated. This means that the door can be opened quickly. A push button, which must be actuated to switch the lock back into its locking position, is mounted on the outside of the handle. An additional manual operation is thus required, which is burdensome. The vehicle owner must learn how to perform this additional operation. The switching of the lock in the one direction via the capacitative sensor and in the other direction via the pus button requires the use of two different systems, which must be coordinated with each other. In addition, each of the two systems requires its own system-specific components. This occupies space in the area of the handle, space which is already in short supply.
It is already known (DE 100 51 055 A1) that two electrodes for two capacitative sensors can be installed in the handle with shielding between them. The two electrodes generate two spatially separate electric fields. The one electrode generates an inner field in the intermediate space between the handle and the vehicle. When a human hand arrives in the area of this inner field, the lock is switched to its release position. The other electrode generates an outer field between the handle and the area surrounding the vehicle. When the authorized person, i.e., the person who is carrying the mobile part belonging to the vehicle, arrives within a defined minimum distance from the handle, the lock is switched to its locking position. In one case, the two electrodes are mounted on the same side of a common circuit board, offset from each other in the vertical direction. This means that a large amount of space is required to install the electrodes in the handle. In another case, the two electrodes are realized on a multilayer circuit board. The production of such multilayer circuit boards, however, is expensive and time-consuming.